The invention pertains to a coin validator unit for a payphone capable of discriminating coin denominations greater than twenty-five cents and providing appropriate signals to the payphone chassis.
In the United States, payphones utilize coin lines or business lines. Coin lines are used by most of the regional bell operating companies (RBOC's) and independent telephone company payphone service providers. Coin lines have tip, ring and ground lines, and utilize a Central Office to provide collect and refund signalling, to provide coin line supervision for such operations as call start and call end, and to determine remote rate determination for other than local calls.
Business lines are generally used by independent payphone provider companies (known as IPP companies). Business lines typically include standard, two-wire tip and ring lines, or normal telephone lines, and thus electronic payphone stations are required because no services are performed at a Central Office. Thus, each electronic payphone station utilized by the IPP company controls its own collect and refund operations, and sets its own call rates. The IPP company leases the business lines from a telephone company, and operates the payphone station business in a manner similar to that of vending machine operators.
Payphones connected to coin lines are commonly known as "Dumb" sets or "Smart" sets. A Dumb set has all telephone line functions performed at the Central Office, while a Smart set is characterized by an electronic chassis which performs some functions of the Dumb set as well as providing additional functions at the payphone station. An example of a Dumb set is a "32B" telephone in wide use in "Western-Electric Company"-style housings. Smart sets are typically designed to replace Dumb sets and contain circuitry to perform some or all of the Central Office functions in the payphone chassis. For example, the circuitry of a Smart set for use on a coin line may add such functions as audit and diagnostic capabilities at the payphone station.
When a call is initiated, a coin validator inside the payphone outputs signals to the payphone chassis as nickel, dime and quarter coins are accepted. In the case of a Smart set the signalling depends upon the chassis being used. The Smart set rates its own calls, so when business lines are being used, if the initial rate set in the chassis of the Smart set is met then the call is permitted to go through. In the case of a Smart or Dumb set connected to coin lines, the chassis generates coin signal pulses for the Central Office according to telephone company specifications.
The United States Mint plans to replace the Susan B. Anthony dollar coin with a new one-dollar denomination coin. The new U.S. dollar coin is slightly larger than the Washington-head quarter currently in circulation, and is made of a bi-metallic material, having an outside gold-color metal coating surrounding a core of another metal. It would be advantageous if payphones currently in use could accept the new dollar coins, particularly for long distance calls that typically cost several dollars. However, the existing payphone infrastructure for coin lines, which includes both the Dumb and Smart sets currently in use, does not include the capability to accept and process dollar coins.